Hello About A Week Ago I Had My Marina I'd

Hello about a week ago I had my marina I'd removed after having it for over the 5 years the same day it was removed I started to bleed for the first few days red an then for the other few days brown I had unprotected sex an my period just stopped . am on birth control pills but I'm also taking a antibiotic an my Dr said I needed to use an not her form of contraceptive for at least a month. I've only been on the pills for 5 days is there any chance I could be pregnant?? The only symptoms I have are nausea an I'm a lil Moody but that could be from the meds.